1. Technical Field
The present disclosure relates to an apparatus for measuring a winding angle of a carbon fiber being wound on a base material and a method of measuring the winding angle.
2. Description of Related Art
As a method of manufacturing a high pressure fluid tank, a so-called filament winding method (hereinafter, referred to as a “FW method”) including winding a carbon fiber obtained by previously impregnating a liner serving as a base material of a tank with a thermosetting resin or an ultraviolet-curing resin to multiple plies and then curing the carbon fiber using heat or ultraviolet light, and forming a fiber-reinforced resin layer having high strength on a surface layer of the liner may be used. In addition, as a type of winding for the carbon fiber, hoop winding in which a carbon fiber is wound substantially perpendicularly to an axis of a liner and helical winding in which a carbon fiber is wound on the liner in a helical shape are known. In helical winding, a carbon fiber is wound to form various predetermined angles with respect to an axis of the liner. When the FW method is used, in order to obtain a desired strength, the carbon fiber needs to be wound at a predetermined angle with respect to the liner. Here, a technology of imaging the liner in a state in which the carbon fiber is being wound using a CCD camera, specifying a winding angle of the carbon fiber from the obtained image and determining whether the carbon fiber is being wound at an appropriate angle has been proposed (see Japanese Patent Application Publication No. 2014-233852 (JP 2014-233852 A)). Further, in relation to a carbon fiber or a paper fiber, various technologies for measuring a thickness of the fiber of a product (a sheet-shaped product such as paper or the like), in which these are used, or an orientation of the fiber have been proposed (see Japanese Patent Application Publication No. H11-269790 (JP H11-269790 A) and Japanese Patent Application Publication No. 2013-160745 (JP 2013-160745 A)).